/**
 * Copyright (C) Gustav Karlsson
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.github.kagkarlsson.scheduler.task.schedule;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;

final class CompositeParser implements Parser {
    private final List<Parser> delegates;

    private CompositeParser(List<Parser> delegates) {
        this.delegates = delegates;
    }

    @Override
    public Optional<Schedule> parse(String scheduleString) {
        return delegates.stream()
            .map(it -> it.parse(scheduleString))
            .filter(Optional::isPresent).map(Optional::get)
            .findFirst();
    }

    @Override
    public List<String> examples() {
        return delegates.stream()
            .flatMap(it -> it.examples().stream())
            .collect(Collectors.toList());
    }

    static CompositeParser of(Parser... parsers) {
        if (parsers == null || parsers.length == 0)
            throw new IllegalArgumentException("Unable to create CompositeParser");
        return new CompositeParser(Arrays.asList(parsers));
    }
}
